The oxidative degradation of several fragrant aldehydes in an antiperspirant base has been investigated. The different products formed have been detected and identified by GC-MS. It is shown that, besides the oxidation products, i.e. mainly the corresponding acid resulting from the Baeyer-Villiger reaction, several unexpected chlorinated products are formed through interactions with aluminium chlorhydrate and the suspension agent. The supposed intermediate in the chlorination pathway is the acyl hypochlorite R(CO)OCl which can react according to either an ionic or a radical route. Reactive species involved in these mechanisms are Clδ+ and Cl*, respectively. The common intermediate for the autoxidation and oxychlorination processes is the peracid R(CO)OOH.
